http://repository.ou.ac.lk/handle/94ousl/3433 Sun, 30 Aug 2026 12:01:50 GMT 2026-08-30T12:01:50Z http://repository.ou.ac.lk/handle/123456789/4166 Towards Sustainable Laboratory Practices: Eco-Friendly Treatment of Decentralized Wastewater Karthika, K.; Pathinayake, V.; Niruparan, S.; Ranaweera, M. S. K.; Athapattu, B. C. L. Wastewater from laboratories are less considered due to their low quantity and decentralization even though it gives detrimental impact to the human and environment. Investigate the contaminants in laboratory wastewater and find an efficient and economical treatment for small scale laboratories. Prototype model of horizontal flow constructed wetland system with bio-geo filters designed, constructed and operated with locally available utilized materials as filter media. Isotherm and kinetic studies carried out for Cinnamon and Neem biochar and clay composite. Laboratory wastewater diluted to desirable pH with pipe borne water was allowed to pass through the treatment system. Higher removal efficiencies of 80% BOD5 and 86% COD observed in the treatment system may due to the presence of biofilm in final treatment tank and clay: neem biochar composite 1:1 as filter media. Operating the treatment system of horizontal flow constructed wetland with bio- geo filters gives eco-friendly and efficient solution for small scale, decentralized highly contaminated laboratory wastewater with heavy metals. Wed, 01 Jan 2025 00:00:00 GMT http://repository.ou.ac.lk/handle/123456789/4166 2025-01-01T00:00:00Z http://repository.ou.ac.lk/handle/123456789/4165 Development of a Retro-Reflective eco-friendly clay rooftile to mitigate the Urban Heat Island (UHI) effect Karunanayake, K.M.I.P.B.; Andradi, D.M.A.M.S.R.; Weerabangsa, M.Z.; Athapattu, B.C.L. The Urban Heat Island (UHI) effect, where the urban areas experience higher and warmer temperatures compared to surrounding rural areas is currently becoming a serious climatic phenomenon common to a lot of large cities around the world. This rise in urban temperatures lead to an increase in energy consumption of buildings and moreover, thermal discomfort to people and affects the quality of human life. There have been reported cases that this high temperature has adversely affected infants, elderly people and people with poor health conditions. Several strategies have been proposed and developed to overcome the UHI effect. This study is focused on developing a rooftile as a mitigation strategy for UHI. Sieve analysis was done and 1.18mm to 0.6mm waste glass particle size was selected as the optimum particle size for designing the reflective layer. Then rooftile was designed by applying the reflective layer, RR glass bead layer and protective sheet and Retro-reflectivity testing was done to check the RR properties of developed Rooftiles. The temperature around Wayamba Royal College, Kurunegala, Sri Lanka has been analyzed in the current study. It is located in a highly crowded area with high relative humidity and temperature. Field temperature data was collected from 15th of April to 19th of April using a pre-prepared electronic setup. The developed rooftile has reduced the surface temperature by 11.81 °C in the peak temperature hour of 11a.m to 12 noon on 19th of April. Therefore, this study explains the concept of UHI and the efficiency of RR rooftiles in mitigating the UHI effect. Wed, 01 Jan 2025 00:00:00 GMT http://repository.ou.ac.lk/handle/123456789/4165 2025-01-01T00:00:00Z http://repository.ou.ac.lk/handle/94ousl/3499 Design and Fabrication of Sustainable Flat Washers Using Textile Fabric Waste Kumara, Duwage Samitha Dasun; Yoganathan, Thavalakshman; Thanihaichelvan, Tharsika Sri Lanka's vibrant textile and apparel industry generates a substantial amount of textile waste, particularly discarded denim, from its manufacturing processes. Both large-scale production facilities and small garment workshops contribute to this accumulation, making denim waste an abundant, yet largely untapped, resource and a significant pollutant. Currently, most discarded denim ends up in landfills, where synthetic dyes and chemical finishes contaminate ecosystems. To mitigate this environmental impact, this research investigates the feasibility of designing and fabricating sustainable flat washers using a denim fabric waste composite. The composite material was prepared by embedding denim fabric waste into an epoxy resin matrix, which was then crosslinked using a methyl ethyl ketone peroxide catalyst. Different denim fiber-to-resin ratios (1:15, 1:20, 1:25, and 1:30) were prepared according to ASTM standards to investigate their mechanical properties, including compressive strength, tensile strength, flexural strength, and hardness. The 1:20 denim fiber-to-resin ratio composite consistently exhibited superior mechanical properties compared to the other composites. The 1:20 denim to resin ratio composite showed the flexural strength of 356.67 MPa which suggests the material's capability to withstand bending loads effectively. The tensile strength of 5.33 MPa was achieved by 1:20 fiber to resin composite indicating sufficient durability for tension-based applications and also exhibited compressive strength of 29.47 GPa highlights the material's ability to resist high compressive forces, making it suitable for heavy-load applications. Although their hardness is lower compared to conventional washers made from aluminum and mild steel, they still provide adequate hardness for many applications. The findings underscore the potential of using recycled textile waste as a viable alternative to traditional materials, offering environmental benefits without significantly compromising mechanical performance. This makes the 1:20 ratio composite flat washers a promising option for applications where sustainability is a key consideration, such as induction motor holder, fan head screw, automobile engine holding place and bicycle rear wheel axle washers. This work contributes to Sustainable Development Goals (SDGs) 9 and 12 in Sri Lanka. Wed, 01 Jan 2025 00:00:00 GMT http://repository.ou.ac.lk/handle/94ousl/3499 2025-01-01T00:00:00Z http://repository.ou.ac.lk/handle/94ousl/3498 Unrefined Montmorillonite Nanoclay-Cinnamon Wood Biochar Composite for Simultaneous Removal of Hardness and Fluoride in Groundwater Ranaweera, M.S.K.; Karthika, K.; Niruparan, S.; Vithanage, M.; Athapattu, B.C.L. It was aimed to synthesize an adsorbent for fluoride and hardness removal using a nanoclay-biochar composite from unrefined Montmorillonite (MMT) clay from the Murunkan in Mannar, Sri Lanka. Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Scanning Electron Microscope (SEM), and Thermal Gravimetric Analysis (TGA) were employed to characterize the materials. FTIR, XRD, and TGA analyses indicated the presence of MMT clay mineral in the sample. The SEM image of the composite confirmed the successful binding of MMT onto the biochar through a flaky appearance along the porous morphology. Further, the surface texture of clay and biochar could support hardness and fluoride removal by enhancing adsorption. The results obtained from CHN analysis show that the biochar sample was rich in carbon, which helps in the sorption of hardness and fluoride. The adsorption isotherm data of all the adsorbents were well fitted to the Temkin isotherm model, suggesting that the removal of hardness and fluoride onto the adsorbent indicates a heat of sorption. The kinetic adsorption data of all the adsorbents were well fitted to the pseudo-first-order kinetic model, indicating the dominant contribution of the physisorption mechanism. However, since the measured adsorption was minimal, a modification to the nanoclay-biochar composite is required for higher sorption efficiency by enhancing the active sites on sorbents to purify groundwater that con Wed, 01 Jan 2025 00:00:00 GMT http://repository.ou.ac.lk/handle/94ousl/3498 2025-01-01T00:00:00Z